1. Field of the Invention
This application claims priority under 35 U.S. C. .sctn..sctn.119 and/or 365 Patent Application No. 98-2727 filed in Korea on Jan. 31, 1998; the entire content of which is hereby incorporated by reference.
The present invention relates to a washing machine of a type wherein a motor drive shaft is coaxial with a pulsator rotation axis and whose motor and a clutch assembly are directly engaged with each other, and more particularly to a motor-clutch assembly of such a washing machine.
2. Description of the Prior Arts
A washing machine is an appliance for making a water stream in a washing and dehydrating tub (hereinafter, referred to as a dehydrating tub) by means of a mechanical force. The washing machine thereby stimulates a chemical operation of a detergent as well as applies physical operation, such as a friction, impact and the like to clothes to be washed so as to enhance washing effect in a short time. Recently, a full-automatic washing machine performs a rinsing and a dehydrating process as well as a washing process.
Such a full-automatic washing machine has a pulsator and driving apparatus for driving the dehydrating tub. The pulsator operates to form the water stream in the dehydrating tub, and the dehydrating tub is driven to apply centrifugal force to clothes to be washed during a washing operation. The driving apparatus of the dehydrating tube includes a motor for generating a driving force, and a clutch assembly for reducing the driving force of the motor to a predetermined degree and then selectively transmitting the adjusted driving force to the pulsator and the dehydrating tub.
In the conventional washing machine, the motor and the clutch assembly are connected with each other through a belt. In recent, however, a washing machine is widely used, in which the motor drive shaft is coaxial with a pulsator rotation axis (hereinafter referred to as a direct engagement type washing machine), and wherein the motor drive shaft and the clutch assembly are disposed along a common axis thereof, because of the problems of vibration and noise.
Such a motor-clutch assembly is described with reference to the accompanying drawings as follows.
FIGS. 7 and 8 show a motor-clutch assembly of the direct engagement type washing machine.
As shown in the drawings, the motor-clutch assembly is installed at a lower side of a dehydrating tub 2. The motor-clutch assembly is comprised of a motor 20, a pulsator driving force transmission section 30, a dehydrating tub driving force transmission section 40 and a clutch section 50.
The motor 20 is comprised of a stator 21, a rotor 22, and a driving shaft 23. The pulsator driving force transmission section 30 is comprised of a planet gear assembly 31 for reducing a rotational force of the driving shaft 23, and a pulsator shaft 33 for receiving a rotational force from the planet gear assembly 31 and then transmitting the rotational force to the pulsator 3. The planet gear assembly 31 is comprised of a sun gear 31a installed at an upper portion of the driving shaft 23, planet gears 31b engaged with the sun gear 31a and a ring gear 31c. The planet gear assembly 31 is engaged with the pulsator shaft 33 through a carrier 35.
In addition, the dehydrating tub driving force transmission section 40 is formed with the sun gear 31a, a gear case 41 rotatably installed at a circumference of the driving shaft 23, a drum 43 installed at an outer surface of the ring gear 31c in a state of being engaged with the gear case 41, a dehydrating tub shaft 45 of which bottom portion is engaged with the drum 43, and a flange member 47 engaged between the upper portion of the dehydrating tub shaft 45 and the dehydrating tub 2. The gear case 41 is rotatably supported on a bottom portion of a lower housing 14 by bearings 42, and the drum 43 is rotatably supported on an upper portion of an upper housing 13 by another bearings 44.
A clutch section 50 is comprised of an upper clutch 51, a lower clutch 53, and a clutch lever 55.
The upper clutch 51 is engaged at a lower circumference of the gear case 41 by a spline to be capable of moving up and down. A coil spring 57 is disposed between the upper clutch 51 and the bearings 42 which rotatably support the gear case 41. The coil spring 57 elastically pushes the upper clutch 51 downward.
The lower clutch 53 is fixed on the driving shaft 13 at the upper portion of an upper motor housing 12.
The clutch lever 55 is a Y-shaped member as shown in FIG. 8, and it is capable of pivoting about a pivot shaft 55a. The clutch lever 55 is elastically and upwardly supported by a clutch spring 59 which is installed on the pivot shaft 55a. Accordingly, the clutch lever 55 supports the upper clutch 51 upwardly to maintain the upper clutch 51 and the lower clutch 53 to be separate from each other. The clutch lever 55 has a pin 55b at the rear side thereof which is extended upwardly. Also, the clutch lever 55 has a pair of rollers 55c at both front sides thereof which are contacted with a lower surface of the upper clutch 51 so as to prevent the clutch lever 55 from being worn out or generating noise which may occur by the contact with the upper clutch 51.
Meanwhile, a brake band 61 is engaged with a brake spring 63 and a brake lever 65. The brake lever 65 is disposed near the pin 55b.
The reference numeral 11 in the drawing denotes a lower housing of the motor, and 15 and 16 denote bearings for supporting the driving shaft to be capable of rotating.
The motor-clutch assembly constructed as above operates as follows.
First, during a washing operation, the motor-clutch assembly keeps the state shown in FIGS. 7 and 8. That is, the clutch lever 55 is elastically supported upwardly by the clutch spring 59, and thereby the upper clutch 51 is separated from the lower clutch 53. Accordingly, the driving force of the motor 20 is not transmitted to the gear case 41 which is rotatably installed at the circumference of the driving shaft 23, but to the sun gear 31a. The rotational velocity of the sun gear 31a is reduced by the planet gear assembly 31 to be transmitted to the pulsator shaft 33, and then the pulsator 3 engaged with the pulsator shaft 33 is rotated.
Second, during the dehydrating operation, a brake lever 65 is pulled by a drain motor (not shown) for opening/closing a drain valve, whereby the brake lever 65 pivots about a brake supporting pin 65a. At this instance, a rotation block 65b formed at one side of the brake lever 65 pushes the pin 55b, so that the clutch lever 55 pivots downwardly about the pivot shaft 55a as shown in FIGS. 9 and 10. Thus, rollers 55c of the clutch lever 55 are separated from the lower surface of the upper clutch 51. When the clutch lever 55 is separated from the upper clutch 51, the upper clutch 51 is no longer supported upwardly. Consequently, the upper clutch 51 is moved downwardly by its own weight and elastic force of the coil spring 57, and then is engaged with the lower clutch 53.
As the upper clutch 51 and the lower clutch 53 are engaged with each other, the driving force of the motor 20 is now transmitted to the upper clutch 51 through the lower clutch 53 which is rotated along with the driving shaft 23. As the upper clutch 51 is rotated, the gear case 41 engaged therewith by spline is also rotated, and the rotational force generated from the rotational movement thereof is transmitted to the dehydrating tub 2 through the drum 43 engaged with the gear case 41, the dehydrating tub shaft 45 engaged with the drum 43, and the flange members 47. Consequently, the dehydrating tub 2 is rotated to perform the dehydrating process.
However, in the conventional washing machine, the clutch lever 55 supports the upper clutch 51 only by a pair of rollers 55c installed at both front sides thereof. Accordingly, the supporting force is not sufficient, so the washing machine may not operate normally if the washing machine is declined or vibrates. Moreover, in case the tension of the clutch spring 59 elastically supporting the clutch lever 55 upwardly is weak, the force for supporting the upper clutch 51 becomes accordingly weak. Therefore, the operation of the clutch is not smoothly performed.